He is engaged, and he has been dealing with an injury or two (knee for sure). He played Roland Garros and lost in the first round. I'm pretty sure this is his last year on tour, his body is just too banged up to play his style of tennis. He had a decent career, I'm sure he will retire with very few regrets.

He might just want one more US Open match. If his ranking isn't high enough, good shot at a wildcard, where he can formally "say goodbye."

I think he was at around 95th in the world prior to the French Open or something. I remember reading a recent interview he did where he was saying he needs surgery, but he's not going to bother until after he's retired, since he's nearing the end of his career anyway.